Is there a way to both check a macro is defined and it equals a certain value at the same time

Question

I regularly use object-like preprocessor macros as boolean flags in C code to turn on and off sections of code.

For example

#define          


        

Answer 1

Yes you can check both:

#if defined DEBUG  &&  DEBUG == 1
#  define D(...) printf(__VA_ARGS__)
#else
#  define D(...)
#endif

In this example even when #define DEBUG 0 but it is not equal to 1 thus nothing will be printed.

You can do even this:

#if defined DEBUG  &&  DEBUG
#  define D(...) printf(__VA_ARGS__)
#else
#  define D(...)
#endif

Here if you #define DEBUG 0 and then D(1,2,3) also nothing will be printed

DOC